The invention pertains to a concrete mixer truck. More specifically, the invention pertains to a concrete mixer truck that uses a mixer barrel with a front-end discharge.
Typically, there are two basic styles of concrete mixer trucks. One style of concrete truck has a mixer barrel that discharges the concrete at the rear end thereof. This is a rear-end discharge style of concrete mixer truck. Another style of concrete mixer truck uses a mixer barrel that discharges concrete at the front end thereof. This type of truck is a front-end discharge style of concrete mixer truck. In this regard, U.S. Pat. No. 4,009,868 to Blind discloses a front-end discharge transit concrete mixer and U.S. Pat. No. 5,192,178 to Silbernagel discloses a front end discharge concrete mixer wherein these two patents are hereby incorporated by reference herein.
Current front-end discharge concrete mixer trucks utilize an engine located at the rear of the truck. The presence of the engine at the rear of the truck has a number of drawbacks. These drawbacks are set forth below.
The typical separation of the frame rails on current front-end discharge concrete mixer trucks is about thirty-four inches. Such a narrow separation presents several drawbacks. U.S. Pat. No. 3,603,565 to Johnson discloses a support frame for a concrete mixer truck wherein such patent is hereby incorporated by reference herein.
One drawback with a thirty-four inch frame rail separation, the industry standard separation, is that the engine can be lowered only so far due to interference and clearance of the engine protrusions and accessories (e.g., gear drives, turbo chargers, alternators, starters, filters, exhaust tubing, and the like) thereof. Many manufacturers remove portions of the frame rail flanges to provide additional clearance for installation and maintenance of engine components. The design compromise that removes portions of the frame rail flanges reduces the strength of the frame rail assembly. In addition, the height of the frame rail webs are somewhat design restricted, even though the height of the frame rail web is the most effective way to increase the frame rail strength. The consequence of this is that the concrete mixer truck design is compromised and weakened and incurs higher maintenance costs as it utilizes standard frame rail separation. It is seen that by providing a frame rail separation wider than the industry standard of thirty-four inches, the engine and its accessories can fit between the frame rails so as to be lower than in current concrete mixer trucks so as to provide for a lower center of gravity without compromising the strength of the frame rail assembly.
By providing a wider frame rail separation, and hence, a lower engine mounting, there is an improvement in the accessibility to the engine for service. By providing a wider frame rail separation, there is more space for the mixer barrel and for laterally positioning the cab. It is thus desirable to provide a front-end discharge concrete truck that has a wider frame rail separation.
One drawback pertains to the weight distribution on the chassis of the truck. More specifically, the presence of the engine and its associated structure at the rear of the chassis places a great amount of weight toward the rear of the chassis. It would be desirable to provide a front-end discharge style of concrete mixer truck that has an improved weight distribution on the chassis so that less weight is on the rear of the chassis, and more evenly distributed along the length of the chassis.
Another drawback with the current rear engine front-end discharge concrete mixer truck is that a so-called "around the corner" drive train is necessary to accommodate the rear engine truck. Such a drive train is more expensive than a conventional drive train. Such a drive train is also more complex, and more expensive, to service than a conventional drive train. It would therefore be highly desirable to provide a front-end discharge concrete mixer that does not need an "around the corner" drive train, but can instead, use a conventional type of drive train.
Still another drawback with the present rear engine front-end discharge concrete mixer trucks is the presence of a chassis that has an extended length. The extended length of the chassis is necessary to accommodate the rear engine. Because of the extended length of the chassis, there is a restriction on the maneuverability of the truck at the job site. The extended length of the chassis to accommodate the rear engine also prevents the use of simple and more conventional styles of tag wheel-axle arrangements. U.S. Pat. No. 5,018,593 to Hermann discloses a high lift tag axle for a concrete truck wherein such patent is hereby incorporated by reference herein. Furthermore, the extended length of the chassis requires the use of longer, and less conventional, hydraulic systems for the rearward PTO. It would be desirable to provide a front-end discharge style of concrete mixer truck that does not require an extended chassis.
Still another drawback with rear engine concrete trucks is that an unconventional cooling system is necessary so that the radiator has adequate ventilation thereby providing adequate cooling capacity. Such an unconventional cooling system is expensive. It would be highly desirable to provide a front-end discharge style of concrete mixer truck that uses a conventional cooling system for the engine.